Magnetic structure for use in ion-traps



y 1951 G. J. MUCHER 2,552,342

. MAGNETIC STRUCTURE FOR USE IN ION-TRAPS Filed Nov. 17, 1949 IN V ENTOR.

Patented May 8, 1951 MAGNETIC STRUCTURE FOR USE IN ION-TRAPS George J.Mucher, Rochester, N. H., assignor to Clarostat Mfg. 00., Inc., Dover,N. H., a corporation of New York Application November 17, 1949, SerialNo. 127,960

This invention relates to a structurally and functionally improved iontrap especially intended for association with a cathode ray tube such asis used in television receivers.

It is an object of the invention to furnish a unit of apparatus whichmay readily be applied to the neck of an electronic tube and maythereupon be adjusted with facility with respect to said tube in bothrotative and axial directions.

A further object is that of furnishing an ion trap which when onceadjusted to proper position will remain fixed against any probability ofaccidental displacement with respect to the part upon which it ismounted; the adjustments achievable by shifting the trap being suchthat, without difiiculty, an operator may relate the same to a giveninstallation with such precision that the best operating results of theelectronic tube are readily achieved.

Another object is that of furnishing a device of this type which willembody relatively few parts each individually simple and rugged inconstruction, such parts being capable of quantity production andassemblage by relatively unskilled. labor, and when assembled furnishinga unit operating over a long period of time with freedom from alldifiiculties.

With these and other objects in mind. reference is had to the attachedsheet of drawings illustrating practical embodiments of the inventionand in which:

Fig. 1 is a fragmentary side elevation of an electron tube with one formof trap mounted thereon;

Fig. 2 is a face view of such trap;

Fig. 3 is a sectional side view taken along the lines 3-3 and in thedirection of the arrows as indicated in Fig. 2;

Fig. 4 is a sectional view taken along the lines 4-4 and in thedirection of the arrows as indicated in Fig. 3;

Fig. 5 is a view similar to Fig. 4, but showing an alternative form ofconstruction; and

Fig. 6 is a transverse sectional view taken along the lines 66 and inthe direction of the arrows as indicated in Fig. 5.

Primarily, referring to Fig. l, the numeral Ii) indicates the neckportion of a cathode ray tube which may be provided with the usual plugbase H. In accordance with conventional practice,

3 Claims. (Cl. 313-45) this base is larger than the neck of the tubes.The complete tube and its component focusing and deflecting mechanismhave not been shown in that they comprise no part of the presentinvention. It suffices to say that within the neck of the tube there isprovided the usual electron gun in which the necessary beam is generatedand directed towards the target area or screen at the end of the tube.The electron beam is focused and deflected to trace a pattern on thetarget screen of the tube. The focusing coil and deflector are locatedadjacent the neck. of the tube to the left of the ion trap as viewed inFig. l; the focusing means being usually disposed between the ion trapand the deflecting means.

The electron beam includes both ions and electrons. It is most desirableto prevent the bombardment of the viewing screen by the ions. The latterbeing many times heavier than electrons and varying widely in weight,their inertia is greater than the power of the deflection means todeflect them over the full area of the screen. Thus, the screen of thecathode ray tube may have a relatively small area subjected to anintensive bombardment. Under these circumstances this area of the screenwould break down after a relatively short period of time. The ion trapof the present invention permits of a controlled deflection of the ionssuch that injury to the screen will be prevented.

One preferred form of ion trap has been shown in Figs. 5 and 6. In thoseviews the numeral I2 indicates a magnet which is preferably U-shaped insection and to the opposite ends of which arms l3 are applied. Thesearms may be secured in position by means of a securing element l3 whichhas its opposite ends extending through openin s in the arms and isheaded beyond the same; its shank extending within the space defined bythe legs of element l2. This shank as shown especially in Fig. 6, ispreferably non-circular in cross section so as to prevent relativerotation of the parts.

Arms 13 are bent or extended so as to project upwardly and outwardly asindicated at I4 and then preferably in a purely vertical direction. asat I5. Spring clips 16 which may be of relatively light stock haveengaging portions I! adjacent their outer ends. Their bodies 13 extendin face to face contact with the vertically probeen used tode'signate'the same parts.

dition, however, it will be noted that in the first jecting portions andterminate at their lower ends in offset portions I9. These extendthrough openings formed in the arms preferably at points adjacent thejuncture of portions l4 and I5. Rivets 2| may secure the bodies l8against the inner faces of portions 55. In this manner the clistructures are firmly mounted and braced against deflection in so far astheir inner ends are concerned.

Normally the contact portions ll of the clip I6 will ocupy the positionindicated in dotted lines in Fig. 5. It is preferred that at least theinner surface of the upwardly and outwardly extending parts I 4 becovered with a layer of cushioning material such as rubber. To this endsleeves 22 of such material may encircle those portions. A structure isthus provided which may readily be expanded to pass over the baseportion l l of the tube ID by simply springing the clips or arms l6outwardly. When the unit occupies a position upon the neck of theelectronic tube, then the clip or resilient arm portion It will occupy aposition such as indicated in full lines in Fig. 5. In such position itwill be 'apparent that the two engaging portions will bear against theouter face of the tube neck and will yieldingly urge angularly extendingparts I4 of the legs into contact with the outer neck surface. Suchcontact will not beinjurious because of the cushioning material 2| whichis preferably provided. Also, that cushioning material will frictionallyengage the surface of the neck in a manner such that unless the trap isdeliberately shifted with respect to that surface, the frictionalcontact of the parts will prevent accidental movement.

In any event, it will be apparent that with this unit mounted upon theneck of the tube, an operator may :readily adjust the same axially ofthat portion. This adjustment will continue until the stream ofelectrons discharged by the tube gun is being dispersed to bestadvantage over the surface of the screen. Thereupon the units may berotated with respect to the tube neck in order to again assure properdeflection. Aswill readily be appreciated the rotational adjustmentmight be resorted to prior to the axial adjustment, or both axialshifting and turning might be simultaneously resorted to.

The structure shown in Figs. 1 to 4 is basically substantially identicalwith the structure hereto- For this reason similar reference numeralshave In adgroup of figures a mounting 23 is provided which maybe in theform of a strip having angularly disposed faces extending throughout thegreater part of a circle. These faces may be generally parallel to theiradjacent arm portions. This strip is provided with a pair of rearwardextensions 24 which may be interposed between portions I5 and i8 andthrough which the rivets 2| may pass. This strip is formed ofnon-magnetic material such as brass and may be provided with a pluralityof forwardly extending portions 25 which are bent to form supports.These receive and mount a magnet 26 in the form of a split ingly engagedby the mounting portions 25. Accordingly, frictional engagement betweenthe parts will occur such that the ring 26 will not be accidentallyrotated with respect to its mounting. However, it may readily be sorotated if sufiicient force is applied.

The magnetic force or strength of the element [2 and the partsassociated therewith may be, for example, from forty-three to fiftygausses. The magnetic force developed by magnet 26 may be, for example,from eight to fifteen gausses. As will be apparent with the partsassembled in the manner shown, they may be expanded so as to pass overthe base ll onto the neck IE! of the electronic tube.

The assembly may be both axially and rotatably shifted with respect tothat neck in order to insure the best operating characteristics of thetube. After this adjustment has been made to best advantage, then magnet26 may be rotated with respect to its mounting. This will permit of afine or Vernier adjustment of the parts which will allow the operator toobtain a functioning of the tube to maximum advantage.

Thus, among others, the several objects of the invention as afore-notedare achieved. Obviously numerous changes in construction andrearrangement of the parts might be resorted to without departing fromthe spirit of the invention as defined by the claims.

I claim:

1. A magnetic structure for supplying a magnetic field in the ion trapof a cathode ray tube, said structure comprising in combination asubstantially square-faced block of material providing a permanentmagnet, relatively rigid arms having their inner end portions disposedone in contact with each of the opposite end faces of said block, saidarms extending upwardly and outwardly from said block and terminating insubstantially parallel end portions spaced from each other a distancegreater than the diameter of a tube neck which they are to encircle,spring clips having their inner ends secured against movement withrespect to the end portions of said arms and extending inwardlytherefrom to have their outer ends spaced from each other andtubeengaging portions adjacent outer ends of said clips.

2. A magnetic structure for supplying a magnetic field in the ion trapof a cathode ray tube, said structure comprising in combination asubstantially square-faced block of material providing a permanentmagnet, relatively rigid arms having their inner end portions disposedone in contact with each of the opposite end faces of said block, saidarms extending upwardly and outwardly from said block and terminating insubstantially parallel end portions spaced from each other a distancegreater than the diameter of a tube neck which they are to encircle,spring clips having their inner ends secured against movement withrespect to the end portions of said arms and extending inwardlytherefrom to have their outer ends spaced from each other, tubeengagingportions adjacent outer ends of said clips, said magnet block beingU-shaped in cross section, a securing element disposed between saidmagnet arms and restrained from rotation by contact with the inner facesthereof and said element extending through the adjacent inner endportions of said arms to maintain the latter against displacement withrespect to said block.

3. A magnetic structure for supplying a magnetic field in the ion trapof a cathode ray tube, said structure comprising in combination asubstantially square-faced block of material providing a permanentmagnet, relatively rigid arms having their inner end portions disposedone in contact with each of the opposite end faces of said block, saidarms extending upwardly and outwardly from said block and terminating insubstantially parallel end portions spaced from each other a distancegreater than the diameter of a tube neck which they are to encircle,spring clips having their inner ends secured against movement withrespect to the end portions of said arms and extending inwardlytherefrom to have their outer ends spaced from each other, tubeengagingportions adjacent outer ends of said clips, a strip connected againstmovement with respect to said arms, extensions projecting from saidstrip and to one side of said arms and clips and mounting portionsforming a part of said extensions to provide a support for a ring-shapedmagnet.

GEORGE J. MUCHER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,149,101 Ploke Feb. 28, 19392,181,850 Nicoll Nov. 28, 1939 2,211,613 Bowie Aug. 13, 1940 2,212,206Holst et a1. Aug. 20, 1940 2,274,586 Branson Feb. 24, 1942 2,456,474Wainwright Dec. 14, 1948 2,460,609 Torsch Feb. 1, 1949 2,472,796Woodbridge June 7, 1949 2,496,127 Kelar Jan. 31, 1950 2,499,065 HeppnerFeb. 28, 1956 2,500,455 Fisher Mar. 14, 1950 2,513,929 Gethmann July 4,1950 2,522,872 Heppner Sept. 19, 1950 2,525,919 Loughren Oct. 17, 19502,539,156 Ostreicher Jan. 23, 1951 2,541,446 Trott Feb. 13, 19512,542,924 Ieppner Feb. 20, 1951 2,544,875 Bennett Mar. 13, 19512,544,898 Obszarny et a1 Mar. 13, 1951

